Reference
TNEB/TNPDCL domestic tariff 2026 — 200 units free subsidy
The real domestic (LT-IA) slab structure the bill calculator uses, including the revised free-electricity subsidy effective 10 May 2026.
Effective 10 May 2026: domestic consumers using 500 units or less in a bimonthly cycle get the first 200 units free (up from 100). Consumers above 500 units continue to get only 100 units free. Rates below follow TNERC Tariff Order No. 6 of 2025 for the domestic (LT-IA) category.
| Units (bi-monthly) | Rate (500 units or less) | Rate (above 500 units) |
|---|---|---|
| 0 – 100 | Free | Free |
| 101 – 200 | Free | ₹4.95 / unit |
| 201 – 400 | ₹4.95 / unit | ₹4.95 / unit |
| 401 – 500 | ₹6.65 / unit | ₹6.65 / unit |
| 501 – 600 | Not applicable | ₹8.80 / unit |
| 601 – 800 | Not applicable | ₹9.95 / unit |
| 801 – 1000 | Not applicable | ₹11.05 / unit |
| 1000+ | Not applicable | ₹12.15 / unit |
How the 200 units free subsidy actually works
Tamil Nadu's new state government revised the domestic free-electricity subsidy effective 10 May 2026, as one of its first major welfare announcements. If your total bimonthly consumption is 500 units or less, the first 200 units of energy charge are free — up from the earlier 100-unit subsidy. Cross 500 units in the same cycle and the free allowance drops back to 100 units, with the remaining consumption priced on the steeper slabs shown above. Around 90% of Tamil Nadu's domestic consumers use 500 units or less bimonthly and benefit directly from the expanded subsidy.
How Tamil Nadu domestic slabs actually work
The most common billing misunderstanding in Tamil Nadu is assuming that crossing into a higher slab charges every unit at the higher rate. It does not. The tariff is telescopic — applied in steps: the first block of units is charged at the first rate, the next block at the second rate, and so on. Only the units above each threshold are charged at the higher rate.
Two worked examples
350 units (500 or less): the first 200 units are free. The remaining 150 units (201–350) are charged at ₹4.95, giving 150 × ₹4.95 = ₹742.50.
600 units (above 500): the free allowance drops to 100 units. The next 300 units (101–400) cost 300 × ₹4.95 = ₹1,485. The next 100 (401–500) cost 100 × ₹6.65 = ₹665. The final 100 (501–600) cost 100 × ₹8.80 = ₹880. Total: ₹3,030 — over four times the first example's bill for less than double the units, because both the subsidy cut and the steeper slabs hit at once.
Why your bill still jumps in summer
Because the structure is progressive, an extra 100 units in May costs far more than the same 100 units in December, when your baseline consumption sat in a lower block — and if that extra summer usage pushes your bimonthly total past 500 units, you lose half your free allowance on top of the higher rates. Air conditioning does not just add units, it adds units at the most expensive rate you pay, and can knock a household out of the larger subsidy tier entirely.
Beyond energy charges
- Fixed charges apply per connection regardless of consumption, and are not included in the calculator above.
- Electricity duty is a statutory levy on top of energy charges.
- Billing period length matters: a 66-day cycle bills more units than a 58-day cycle at identical daily usage.
- Arrears from a previous period are added to the current bill and are not part of this period's consumption.
Keeping this page honest
Tariffs and subsidies in Tamil Nadu are fixed by the Tamil Nadu Electricity Regulatory Commission (TNERC) and the state government, and are revised from time to time. The figures above reflect TNERC Tariff Order No. 6 of 2025 and the government's free-electricity subsidy revision effective 10 May 2026. Your latest bill and the official TNPDCL site are always the authoritative source; we note the basis for every figure on our data sources page.